Grundy County, in Missouri, sits in USDA hardiness zone 6a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
On paper, cabbage, hazelnut, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Grundy County holds more than one microclimate.
Soils and elevations shift across Grundy County, so your frost dates and drainage aren't the county average. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Grundy County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Grundy County — the short answer
Grundy County, Missouri: USDA zone 6a, about 208 days between hard freezes, across 279K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 5
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 30
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~208
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 279K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 6a is Grundy County's average, not your lot's — a low corner or a tree line moves it. Against Grundy County's 208-day season, see what your own ground reads.
Heat in Grundy County
Across a year, Grundy County accumulates about 3,433 growing degree days above 50°F, about 320 fewer than the middle Missouri county — ahead of 18 of Missouri’s 115 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Grundy County
Across Grundy County, the ground is predominantly Alfisols, where Armstrong, Gara, and Zook are the most extensive named soil series. The soil is generally somewhat poorly drained with a clay loam surface. Topsoil pH runs about 6.1–6.5, slightly acidic. Rainfall drains through hydrologic group C/D soils.
Soil order
Alfisols
Drainage
Somewhat poorly drained
Prime farmland
12%
Hydric soils
20%
Soil still varies lot by lot — soil types explained.
How the ground varies across Grundy County
The USDA soil survey maps 45% of Grundy County as somewhat poorly drained — but another 55% drains differently: 21% well drained, 16% poorly drained.
Armstrong is the most extensive named soil at 13% of mapped acres, then Gara (12%) and Zook (8%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Grundy County
Each reading below is measured for Grundy County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Grundy County are somewhat poorly drained, in hydrologic group C/D — ground that sheds water slowly.
Beds can stay saturated for days after heavy rain, and the roots of most vegetables, berries, and fruit trees suffocate or rot in soil that never drains.
Raised beds or mounded rows lift roots above the wet zone; choose water-tolerant crops for the lowest spots.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Grundy County runs about pH 6.1–6.5, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredGrundy County runs about 208 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredGrundy County sits in USDA hardiness zone 6a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Grundy County is in
Grundy County sits in the Central Irregular Plains — EPA Level III, inside the wider Great Plains. One consistent ecological setting across the whole county.
What Grows in Grundy County
We scored all 1,086 plants against Grundy County's own USDA zone 6a and its own 208-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Missouri profile.
Is it too late to plant in Grundy County?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 30 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What gets applied to farmland in Grundy County
USGS estimates 140,764 lb of Glyphosate on Grundy County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (54,808 lb) and Atrazine (40,663 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Grundy County — and how to grow with it.
We checked the federal record across Grundy County — 132 documented sites across 7 of the 9 source types we track.
The most significant on record: 5 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Grundy County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Grundy County
Closest first, across Grundy County. Listing isn't leaking, and distance isn't exposure.
- T61N R24W 03ABD1Nitrate · 1.0 mi
- T61N R24W 12CCC1Nitrate · 1.6 mi
- T61N R24W 15DAD1Nitrate · 2.1 mi
- BRANDING IRONUnderground Storage Tanks · 2.2 mi
- GRUNDY ELECTRIC COOPERATIVE INCUnderground Storage Tanks · 2.2 mi
- T61N R24W 15DANitrate · 2.2 mi
- TRENTON ARMORY/OMSUnderground Storage Tanks · 2.5 mi
- GRUNDY COUNTY NURSING HOME DISTRICTUnderground Storage Tanks · 2.6 mi
- CASEYS GENERAL STORE #2008Underground Storage Tanks · 2.6 mi
- TRENTON MAINT LOTUnderground Storage Tanks · 2.7 mi
- TRENTON, MO STOCKPILEToxics Release Inventory · 2.7 mi
- TRENTON MUNICIPAL AIRPORTUnderground Storage Tanks · 2.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Grundy County's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Grundy County.
Total Sites
132
across Grundy County
Risk Level
Moderate
Highest-severity
5 Toxics Release Inventory facilities
Sources Checked
across Grundy County
Severity Distribution
across Grundy County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Grundy County, two things run higher than the national average across Grundy County — PFAS (3 sites) and Nitrate (78 sites). That's not a problem with your land — it's information about it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Grundy County
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Grundy County average
Your land is one point inside Grundy County
Everything above resolves to Grundy County as a whole — one PHZM band and one county frost record, read across 279K acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at county scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better county average.
Your Lot vs the Grundy County Average
Grundy County Average
- ●USDA Zones 6a, averaged across Grundy County
- ●One soil character for all of Grundy County
- ●Frost dates read at Grundy County's scale: Apr 5 to Oct 30
YOUR Parcel
- ✓Your exact zone, not Grundy County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Grundy County
Pull a site-specific report for your exact address in Grundy County, Missouri — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Grundy County averages can't show:
We read public map data around Grundy County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Grundy County average
How we know this about Grundy County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Grundy County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Grundy County
When does frost risk typically end in Grundy County?
The last hard freeze (28°F) in Grundy County typically lands around Apr 5, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Apr 26.
How long is the growing season in Grundy County?
Measured between 28°F hard freezes, Grundy County sees about 208 frost-free days — roughly Apr 5 through Oct 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 26 to Oct 16, about 173 days.
Is the soil safe to grow vegetables in Grundy County?
The federal record around Grundy County shows 132 documented sites, mostly Nitrate entries (78), the nearest Nitrate record about 1.0 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
Everything above is measured at Grundy County's scale — its 6a band and its 208-day season. Your yard writes its own version of Grundy County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Missouri's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Grundy County’s own scale
8 of the readings below were taken at Grundy County's own scale — its own ~208-day span between 28°F freezes, the 3 most extensive soil series mapped here and 132 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Grundy County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Grundy County's own 28°F hard-freeze dates and its ~208-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Grundy CountyUSDA NRCS SSURGO
- 132 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 1.0 miles outFederal environmental registers
- Grundy County's boundary and the 278,587 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~208-day seasonGrowable Ground crop-matching engine
- Grundy County sitting wholly inside the Central Irregular PlainsUS EPA Level III Ecoregions
- Which agricultural compounds go onto Grundy County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Missouri grower plans around — written at state scale, so they stay on the state guidefrom Missouri
What this page can’t tell you
- How the season shifts across Grundy County — the ~208 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Grundy County's 278,587 acreswhy one lot differs from the next →
- Which of those 132 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Grundy Countyread your own land →